Oxygen vacancy mediated polymerization of pyrrole on MoO3 to construct dielectric nanocomposites for electromagnetic waves absorption application

Transition metal oxides (TMOs) with tunable electronic structures and low cost have gained much attention for various applications. However, rational development of TMOs-based electromagnetic waves (EMW) absorbers is still a challenge due to their inherent weak conductivity and loss capacity. Here, we report a delicate oxygen vacancy mediated compounding strategy that the oxygen vacancy can improve the structural properties of molybdenum trioxide (MoO3) to direct the in-situ polymerization of pyrrole, constructing the oxygen vacancy-containing o-MoO3/polypyrrole (o-MoO3/PPy) composites. With the abundant active species aroused from oxygen vacancy and PPy via this design, the great electrical conductivity and excellent dielectric loss capability are simultaneously displayed in o-MoO3/PPy composites. Therefore, the outstanding EMW absorption performance is found at optimized o-MoO3/PPy1, achieving a wide absorption bandwidth of 6.26 GHz, which is remarkably enhanced compared to o-MoO3. This work will provide the valuable strategy for the development of TMOs-based materials for efficient EMW absorption.